A temperature control system that includes a liquid tank which keeps the contents thereof at a constant temperature has been widely used. Recently, in a certain type of the temperature control device, a heat exchanger equipped with a thermo-module that controls temperatures using Peltier effect has been provided for the liquid tank (for example, see Japanese Unexamined Patent Application Publication No. 2000-75935). The heat exchanger equipped with the thermo-module is capable of switching the temperature control between heating and cooling by simply changing the direction where electric current is applied. The aforementioned heat exchanger, thus, may be compact, and especially suitable for the use in a compact liquid tank.
The temperature control device disclosed in the prior art publication noted above includes a liquid tank in which the temperature of a heat exchange medium filled therein is controlled by a heat exchanger equipped with the thermo-module, and a coil tube disposed within the liquid tank. In the temperature control device, heat exchange between the liquid chemical flowing through the coil tube and the heat exchange medium is performed for controlling temperatures, and a stirring bar on the bottom stirs the heat exchange medium so as to be kept at a constant temperature.
In the aforementioned temperature control device, however, the coil tube is simply immersed into the tank filled with the heat exchange medium that is stirred by the stirring bar. It is, thus, difficult to efficiently perform the heat exchange between the liquid chemical flowing through the coil tube and the heat exchange medium.
Another known temperature control device that controls temperatures of fluid within the tank using the heat exchanger equipped with the thermo-module has been introduced, which includes an outer tank that stores the fluid, an inner tank provided within the outer tank leaving a gap therefrom, having a channel formed in its side wall for accommodating an inflow of the fluid, and an opening formed at the center of its bottom, a container immersed in the fluid within the inner tank for storing the liquid chemical subjected to the temperature control, and a stirring member that guides the fluid accommodated through the opening of the bottom of the inner tank toward the upward direction via a space between the side walls of the inner and the outer tanks using a rotary blade provided at the center of the bottom of a portion between the outer and the inner tanks. The thermo-module of the heat exchanger is attached to the outer surface of the side wall of the outer tank such that the temperature of the fluid flowing through the space between the inner and the outer tanks is controlled to a predetermined temperature based on the output of a temperature sensor that detects the fluid temperature (see, for example, Japanese Unexamined Patent Publication No. 2005-127608).
In the aforementioned temperature control device, a container that stores the liquid chemical subjected to the temperature control is disposed within the inner tank such that heat is transferred from the constant-temperature fluid within the inner tank to the liquid chemical. This may cause the problem of taking much time for stabilizing the temperature of the liquid chemical.